CSFB is a technology that uses another radio access network (RAN) in a coverage area of an Long Term Evolution (LTE) system to support a circuit switched (CS) Domain call. A CSFB process enables all CS services, such as a voice service, of user equipment, to be handed over to an access network with a relatively low bandwidth, for example, a Global System of Mobile Communications (GSM) or a Universal Mobile Telecommunications System (UMTS), thereby saving bandwidth resources of an operator.
In an existing CSFB handover method, a corresponding GSM/UMTS cell is generally preconfigured for each LTE cell. When user equipment (UE) needs to use a voice service, the UE is handed over to a GSM/UMTS cell corresponding to an LTE cell on which the UE is currently located. To reduce a voice service setup delay, the existing CSFB handover method generally uses blind handover. That is, when the UE needs to use the voice service, the UE is directly handed over to a preconfigured GSM/UMTS blind handover neighboring cell of the current LTE cell.
During the implementation of the present invention, the inventor finds that the prior art has at least the following problems:
The existing CSFB handover method is applicable to an overlapping coverage area between the LTE cell and the GSM/UMTS cell, but in a non-overlapping coverage area of the LTE cell and the GSM/UMTS cell, CSFB may fail, and consequently, the UE fails to be handed over and cannot use the CS service.